ON/OFF switch for smoke simulation effectors
This is controlled by the Field Weights section of the domain object's physics panel.

There are dials for each type of field, which you can set to 0.0 for OFF and 1.0 for ON.

Another way is to create a collection and seet the effector collections. Put the active field effector in that collection, all other effectors will be ignored for the purposes of the smoke simulation.  Then swap out the effector when you want to change to another field effect.